One session of whole-body heating eased depression more than a sham session did
Claims that heat can ease depression come from this 2016 JAMA Psychiatry trial. Researchers randomly assigned 34 adults with major depression to one session of medical whole-body heating or a sham session.
The paper
Whole-Body Hyperthermia for the Treatment of Major Depressive Disorder
Janssen CW, Lowry CA, Mehl MR, Allen JJB, et al.. JAMA Psychiatry, 2016;73(8):789-795.
See the study at a glance
- Design
- Randomized, double-blind, sham-controlled trial
- People
- 29 adults analyzed (34 randomized)
- Who they were
- Medically healthy adults aged 18 to 65 with major depressive disorder who took no psychiatric drugs and scored at least 16 on the Hamilton depression scale. The average age was 36.7 in the heat group and 41.5 in the sham group.
- What they did
- One session in a medical hyperthermia device. Infrared lamps over the chest and heating coils over the legs warmed each person until core temperature reached 38.5°C, and then came an hour of cooling. The sham ran for the same time with its main lamps switched off.
- How long
- Six weeks of follow-up after one session
These numbers came out of it
−6.53
The heat group scored 6.53 points lower than the sham group on the Hamilton depression scale a week after the session. Lower scores mean milder depression.
−4.27
By week 6 the difference had narrowed to 4.27 points, and it was still statistically significant.
71.4%
In the sham group, 71.4% thought they had received the heat treatment.
29 of 338
The researchers screened 338 people and randomly assigned 34 of them. Twenty-nine made it into the final analysis.
The researchers did this
Researchers at a US university medical center screened 338 adults with major depression and randomly assigned 34 of them to one session of whole-body heating or a sham session. Everyone was medically healthy and off psychiatric drugs. Twenty-nine completed at least one assessment after treatment.Source 1 · Randomized trialWhole-Body Hyperthermia for the Treatment of Major Depressive DisorderJanssen CW, Lowry CA, Mehl MR, et al.. JAMA Psychiatry, 2016.Read the paper ↗PubMed ↗
The heat came from a medical device called the Heckel HT3000. Infrared lamps over the chest and heating coils over the legs ran until core temperature reached 38.5°C, and an hour of cooling followed.Source 2 · Clinical trialThe antidepressant effect of whole-body hyperthermia is associated with the classical interleukin-6 signaling pathwayMac Giollabhui N, Lowry CA, Nyer M, et al.. Brain, Behavior, and Immunity, 2024.Read the paper ↗PubMed ↗ The sham session lasted as long with its main lamps off. Extra light and noise made it feel like treatment.
The trial's main outcome compared the two groups' scores on the Hamilton depression scale. A week after the session the heat group scored 6.53 points lower than the sham group. The difference was 6.35 points at week 2 and 4.50 at week 4, and by week 6 it had narrowed to 4.27. All four differences were statistically significant.Source 1 · Randomized trialWhole-Body Hyperthermia for the Treatment of Major Depressive DisorderJanssen CW, Lowry CA, Mehl MR, et al.. JAMA Psychiatry, 2016.Read the paper ↗PubMed ↗ Adjusting for what participants expected didn't change the result, and side effects were generally mild.
Most people thought they'd had the heat treatment, whichever group they were in. The share was 93.8% in the heat group and 71.4% in the sham group. A later analysis of the trial's blood samples looked at an immune messenger called IL-6. People whose IL-6 signaling rose more right after the session had lower depression scores over the next six weeks.Source 2 · Clinical trialThe antidepressant effect of whole-body hyperthermia is associated with the classical interleukin-6 signaling pathwayMac Giollabhui N, Lowry CA, Nyer M, et al.. Brain, Behavior, and Immunity, 2024.Read the paper ↗PubMed ↗ Another found that 17 genes, including heat shock protein genes, were more active 30 minutes after heat than after sham.Source 3 · Clinical trialWhole-blood transcriptomic response to whole-body hyperthermia in participants with major depressive disorderAkonom TN, Allen MA, Begay TK, et al.. Brain, Behavior, & Immunity - Health, 2026.Read the paper ↗PubMed ↗
The study can't tell you these things
- The analysis included only 29 people from one site.
- Everyone had one session in a medical device, so the trial can't tell you what a home sauna or repeated sessions would do.
- The trial left out anyone on psychiatric drugs or with other medical illnesses.
- The advantage over sham shrank between week 1 and week 6, and follow-up stopped there.
People quote it like this
People usually sum it up as one heat session relieving depression for six weeks. The advantage over sham was biggest at week 1 and smaller by week 6, and the device heated people until their core temperature reached 38.5°C.Source 1 · Randomized trialWhole-Body Hyperthermia for the Treatment of Major Depressive DisorderJanssen CW, Lowry CA, Mehl MR, et al.. JAMA Psychiatry, 2016.Read the paper ↗PubMed ↗Source 2 · Clinical trialThe antidepressant effect of whole-body hyperthermia is associated with the classical interleukin-6 signaling pathwayMac Giollabhui N, Lowry CA, Nyer M, et al.. Brain, Behavior, and Immunity, 2024.Read the paper ↗PubMed ↗ In young adults, three 10-minute rounds in a traditional sauna raised core temperature by 0.4°C.Source 4 · Crossover trialComparison of thermoregulatory, cardiovascular, and immune responses to different passive heat therapy modalitiesAtencio JK, Reed EL, Wiedenfeld Needham K, et al.. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 2025.Read the paper ↗PubMed ↗
From our sister magazine
Sauna Monthly weighs infrared heat against hot-rock saunas
We cited these sources
- 01Janssen CW, Lowry CA, Mehl MR, Allen JJB, Kelly KL, Gartner DE, et al.. Whole-Body Hyperthermia for the Treatment of Major Depressive Disorder. JAMA Psychiatry. 2016;73(8):789-795. doi:10.1001/jamapsychiatry.2016.1031 PMID 27172277
- 02Mac Giollabhui N, Lowry CA, Nyer M, Foster SL, Liu RT, Smith DG, et al.. The antidepressant effect of whole-body hyperthermia is associated with the classical interleukin-6 signaling pathway. Brain, Behavior, and Immunity. 2024;119:801-806. doi:10.1016/j.bbi.2024.04.040 PMID 39848840
- 03Akonom TN, Allen MA, Begay TK, Mason AE, Cole SP, Raison CL, et al.. Whole-blood transcriptomic response to whole-body hyperthermia in participants with major depressive disorder. Brain, Behavior, & Immunity - Health. 2026;54:101225. doi:10.1016/j.bbih.2026.101225 PMID 42004495
- 04Atencio JK, Reed EL, Wiedenfeld Needham K, Lucernoni KM, Comrada LN, Halliwill JR, et al.. Comparison of thermoregulatory, cardiovascular, and immune responses to different passive heat therapy modalities. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology. 2025;329(1):R20-R35. doi:10.1152/ajpregu.00012.2025 PMID 40332494